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How to Manage Pests

Identification: Weed Photo Gallery

Smallflower umbrella sedge

Scientific name: Cyperus difformis (Sedge family: Cyperaceae)

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Life stages of Smallflower umbrella sedge flower seedling mature plant infestation in rice field fruit

Smallflower umbrella sedge, sometimes called smallflower umbrellaplant, a summer annual sedge, is an erect, grasslike plant. In California, it is found in the Central Valley and southwestern regions, to about 1600 feet (550 m). This sedge inhabits pond margins, ditches, and is particularly common in rice-growing areas. It typically grows in wet soil or shallow water, does not tolerate deep water, and grows best on fertile soil. This plant produces thousands of small seeds that become uniformly distributed over the ground. Some biotypes have developed tolerance to certain herbicides.

Seedling

Cotyledons (seed leaves) are more or less football shaped, hairless, translucent, and very tiny, less than 1/25 of an inch (1 mm) long. The first leaf blade is bright green, with three veins, and roughly 1/6 to 1/3 of an inch (4–8 mm) long. At the three-leaf stage, narrow, grasslike leaves grow out in three directions at approximately 120° angles from one another. Seedling roots are sometimes pinkish.

Mature plant

Mature plants grow in clumps, reach about 12 to 16 inches (30–40 cm) tall, and produce round clusters of greenish brown to purplish spikelets at maturity. Several pithy stems, sharply triangular in cross-section and often with concave sides, rise from the base of the plant. Sheaths are closed. There are typically two to four basal leaves per stem that are slightly rough to the touch on the margins near the tips. Each stem has secondary leaves below the flower clusters. Roots are fibrous and sometimes reddish.

Flower

Flowering takes place from May through November. Flowers are greenish brown to purplish and cluster densely to form round, stalked or stalkless flower heads, each having two to three modified leaves below it.

Fruit

The fruit is egg shaped, pale greenish brown, glossy, and very tiny—less than 1/25 of an inch (1 mm).

Reproduction

Reproduce by seed.

Related species/Similar looking plants

Ricefield bulrush
Tall flatsedge
Tall umbrella sedge

More information


Statewide IPM Program, Agriculture and Natural Resources, University of California
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